This invetion relates to the field of potentiometers and more particularly to a miniaturized structure of a potentiometer.
In some of the prior art devices (U.S. Pat. No. 3,531,753, patented Sept. 29, 1970, issued to Stefan O. Geese and U.S. Pat. No. 3,601,743 patented Aug. 24, 1971, issued to Victor G. Mathison et al), a case or a cap of spun sheet metal is attached to a base of a potentiometer by depending legs or lugs which are received in complementary recessed slots formed in the base.
The legs are crimped inwardly so that the cap or a case is secured to the base to form an open-top chamber in which a rotor is held.
However, if the structure of the case of the potentiometer of the prior art is maintained it is difficult to reduce the physical size especially with respect to the thickness of the potentiometer.
Therefore this type of potentiometer may be unable to meet a demand in the market requiring miniaturized potentiometers especially having a reduced thickness.
It is an object of this invention to provide a miniaturized potentiometer having a flat and thin structure with the purpose of meeting this recent market demand.
In some prior art devices (U.S. Pat. No. 3,601,743 patented Aug. 24, 1971 and issued to Vitor G. Mathsion et al), a rotor of a potentiometer is adjusted by inserting a tool in a screw driver slot disposed in a cap thereof and by turning the rotor clockwise or counterclockwise until a top of the rotor touches a stopper disposed on the cap.
If this structure is to be maintained it is also difficult to produce thin potentiometers having a small physical size and to meet the market demand as heretofore explained.
It is another object of this invention to provide a rotor stopper device arranged within a case and a housing thereby facilitating a reduction in the physical size of a potentiometer to be obtained.
The above mentioned objects are achieved by a potentiometer of this invention which comprises: a case, a housing and a rotor which is rotatably arranged in a chamber of the housing. The housing is provided with a pair of projections on both side walls thereof and two pairs of corner projections at four corners thereof respectively while the case of the potentiometer has a pair of bent long legs in which holes are defined to receive the side wall projections of the housing and a pair of bent short walls to cover the top of the housing. The case may be pushed down onto the housing with the pair of beng long legs thereof being slid into vertical grooves arranged between the corner projections of the housing until the side wall projections of the housing are slidingly snapped into the holes of the case and thus the case and the housing may be assembled in one operation. Two end walls of a portion of a narrow strip are arranged on the surface of the rotor to alternatively abut against two vertical walls of a rectangular strip, which is arranged at the inner side of housing hole and is located adjacent to a collector element of the base, whenever the rotor rotates in a clockwise or counter-clockwise direction.